Effect of Radiogenic Helium on Stainless Steel 12Cr18Ni10Ti Structural Changes and Hydrogen Sorption

The tritium trick technique was used to build-up radiogenic helium inside stainless steel 12Cr18Ni10Ti (SS). A great quantity of defects with a mean diameter of 20 nm, most probably platelet-like bubbles with ³He atoms, was observed in ³He-containing samples. The mean density of these bubbles in SS samples containing ~75 appm of ³He is estimated to be 610²⁰ m^-3. Much larger helium bubbles were observed in SS after annealing the samples at T1170 K. Thermal release of radiogenic helium occurs at T>1500 K. The presence of ³He in structural materials causes the formation of an additional state for hydrogen sorption.